Manufactured materials are often used in human and animal bone and joint replacement implantation procedures. Examples of such implants are replacement knee and hip joint components, and dental crowns and bridges. Ideally, such implants would last beyond the life expectancy of the recipient. However often the manufactured material fails in situ and a further replacement is needed. Failure of implants and the revision surgery associated with their replacement present an increasing burden to society, especially with higher life expectancies and the modern disposition to obesity. In the United States, mortality caused by hip fractures alone accounts for approximately 1% of all deaths, resulting in an estimated 33,100 life-years lost annually. In 2004, fractures accounted for 1 to 2% of total health care costs, amounting to a $20 to $40 billion burden that is projected to rise to between $40 and $80 billion in 2015. The American Academy of Orthopedic Surgeons reports an increase in partial hip replacements in the United States from 112,000 in 1998 to 240,000 in 2004. A hip replacement lasts for only about 10 to 15 years and sometimes even fails within the first year. In 2004, there were 46,000 revision hip surgeries.
Many techniques have been developed to control the bulk properties of advanced materials, such as those used in implants. Techniques have also been developed for the preparation and modification of the surface of advanced materials. However, in many applications of advanced materials the structuring of bulk properties and surface properties are inadequate to meet all of the desired characteristics of advanced materials. Examples of such circumstances are at points of interface with other materials where localized stresses may cause a material failure. What are needed therefore are techniques to modify the properties of advanced materials through a controllable depth, such as at localized points of interface with other materials